In a previous post about my Olight S1R Baton II aux LED mod I complained about the protruding center charging contact that drains the battery when placed on a flat, metal surface and also affects the tailstand stability. Today I took this “light that I do not want” and tried to fix this issue.
To my surprise the tailcap/end of the flashlight was relatively easy to disassemble. I didn’t expect this from a shiny, bling-bling, mass market, “premium” flashlight. But I have to say that the flashlight is engineered really well. They could have made a really awesome flashlight with just a high CRI LED.
Here are the parts of the tailcap/end laid out:
From left to right we have:
- Plastic (!) retaining ring that keeps everything at the right place
- PCB with the outer spring and central contact on the back; a curved spring washer contact on the front which makes contact with the tube. Also the riveted central pin that is visible from the outside. (Wait – that pin in negative, but the center of the battery is positive! This means that the rivet and the ring shaped inner contact, that are less than 1 mm apart from each other, have different polarity! But it should be protected by the circuit.) There are also two chips and a few resistors.
- O-ring that sits around the central pin
- A plastic spacer that is slid over the contact and o-ring
- The magnet that sits around the plastic spacer
- Another o-ring that seals the top of the plastic spacer with the hole in the flashlight case
The two chips are labeled “2408 LV15” (probably a AON2408 n-channel MOSFET in DFN package) and “12B” (don’t know what it is). The traces are not visible under the black solder mask.
And now to the fix for the protruding contact: I made a plastic washer, inner diameter 5 mm, outer diameter 8 mm and a thickness of 0.4 mm. This washer is placed around the riveted pin, then everything else is put on top. The o-ring seal should still work, but the contact does not protrude as much as before anymore. 0.6 mm might have been better (it still makes contact with a flat surface, but is at the same height as the outer, silver ring). To put everything back in the tube I used a PVC pipe. This also helps to press the retaining ring far enough.